A different way of looking at galaxy magnitudes

Published galaxy magnitudes can be very misleading to visual
observers for various reasons. Even properly determined
visual magnitudes are not always very useful. Many observers
look at a combination of the total V magnitude and the
average surface brightness, but even that can fail in cases
where the brightness distribution is unusual.

Using techniques similar to those used by researchers in this
field, I have derived total visual magnitudes, magnitudes for a
grid of apparent sizes, and other information for a sample of
galaxies. I also give total visual magnitudes and sizes derived
from the 3rd Reference Catalog of Bright Galaxies (RC3) and that
information should be useful even if you don't like the extra
analysis I've done. Plus, if you are a beginner, I have used
this analysis to identify the most
easily detected galaxies.
I have put together a more detailed
description of the basic problem, the data sources, and my
analysis. The main point being that when you merely detect a
galaxy, you will only be seeing the brightest core region and
integrated magnitudes and average surface brightnesses do not
always accurately predict the detectability or visibility of
that core.

As a start to this project, I have put together data for
galaxies in the Messier and
Herschel 400 lists. That's a total of 260 galaxies, of
which 258 have at least limited data, and about 95% have
significant useful data. You can check out a few
sample fits, which show
the raw data and the best fit to this data.

This data may or may not be useful to you. As I see it, the
main use would involve observing some galaxies, noting how
easily they were detected, and compare your visibility data with
V(1.0), etc. If you barely saw a galaxy with V(1.0)=11.0, then
you will probably have trouble detecting any galaxy with V(1.0)
much fainter than 11.0. I.e. maybe you are trying to see all
the H400 objects with a small telescope under dark skies, or a
large telescope under poor skies, etc. Note again that this
list is geared toward the detection of a galaxy and not
the amount of detail you might see if you have a large enough
aperture and/or dark enough skies.

My personal goal is to see as many galaxies as possible with my
6" telescope from dark skies in the next year or two. I've
observed all of the objects on the list I'm providing, plus many
fainter galaxies. There are more than 2000 galaxies on the full
Herschel list, plus hundreds of other NGC and IC galaxies that
may be within reach. Nearly 3000 galaxies have enough
photometry for me to do my full analysis, and hundreds of others
have partial data. I intend to use this data to help weed out
galaxies that I have no hope of detecting. If you use the
following data in the same way, please be conservative in
assuming that you can't see a galaxy. You may surprise yourself
and sometimes the data is simply wrong!

As you might guess, much of this data was put together in an
automated manner, so there may be a few stupid mistakes lurking.

Galaxy data in the form
of an html table and an Excel spreadsheet and a description of
each column of the table. This is a large table that will take
a moment to download and render.

A list of the best
beginner galaxies based on the core brightnesses in the
previous table. This list contains 22 of the easiest galaxies
for observers at middle-latitudes in the northern hemisphere.